![]() ![]() We conclude that objective methods of refraction based on wavefront aberration maps can accurately predict the results of subjective refraction and may be more precise. However, caution is advised because some tasks, including conventional refraction of defocus, require a biased metric whereas other tasks, such as refraction of astigmatism, are unbiased. ![]() We argue that the accuracy of all methods might be improved by correcting for the systematic bias reported in this study. Three of these were based on pupil plane metrics and two were based on image plane metrics. Five methods emerged as reasonably accurate and among the most precise. We argue that this result was obtained because curvature matching is a biased method that successfully predicts the biased endpoint stipulated by conventional refractions. Paraxial curvature matching of the wavefront aberration map was the most accurate method for determining the spherical equivalent error whereas least-squares fitting of the wavefront was one of the least accurate methods. Precision of astigmatism predictions was typically better than precision for predicting defocus and many methods were better than 0.5D. All methods except one accurately predicted astigmatism to within ☑/8D. Precision of these estimates (as specified by 95% limits of agreement) ranged from 0.5 to 1.0 D. Accuracy for predicting defocus (as specified by the population mean error of prediction) varied from −0.50 D to +0.25 D across methods. We determined the accuracy and precision of 33 objective methods for predicting the results of conventional, sphero-cylindrical refraction from wavefront aberrations in a large population of 200 eyes. ![]()
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